I recently put together a wonderful system based on the JA RM7si MKI with a Simaudio Moon I5. All pieces bought right here on the gon! Still breaking in cables, but I am extremely pleased with the combination. The caveat with this
combo is that is not a 'house shaker'. Depending on your musical taste, you'll find that the I5 provides a significant degree of finese to the RM7's and any acoustic music: jazz combo, classical chamber, etc. I have not tried other amps, but I have noticed alot of talk about the manufacturer using tubes, so maybe something along the lines of a manley stingray may be what you're looking for.